feat: require approval for AI write actions

[mahoshojoHCG]

Summary

• declare explicit read-only, mutating, or destructive risk metadata for every AI tool and classify mixed tools by exact action
• replace direct chat write execution with encrypted, user/conversation-bound pending actions, one-time atomic approval claims, expiration, replay protection, and queryable redacted audit events
• stream approval_required events and add reconnect-safe approve/reject cards with server-enforced second confirmation for destructive actions
• redact protected write parameters from persisted chat history and application logs
• add an EF Core migration plus security coverage for prompt injection, tampering, rejection, expiration, invalid conversations, concurrent approval, reconnect, and replay

Validation

• dotnet test SecondDimensionWatcherReDive.slnx --no-restore (419 passed)
• yarn build
• dotnet tool run dotnet-ef migrations has-pending-model-changes ... --no-build

Closes #8

[chatgpt-codex-connector]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-29T13:43:44.871567Z	03f142e	PR opened

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[chatgpt-codex-connector]

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Reviewed commit: 03f142eb4f

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